As advances in data high density storage technology continue to progress, more homes and business are acquiring computer peripherals capable of reading the new forms of portable data storage media. For example, high-density media such as compact disc--read only memory (CD-ROM) is becoming a popular medium for storing advanced forms of electronic information such as textual, visual (video or photographs) and audio information as well as interactive media. CD-ROMs contain enough storage space to hold the equivalent of 250,000 pages of text, 12,000 images, 1.5 hours of video, 500 paperback books or 430 magazines. Moreover, CD-ROM technology supports an extremely cost effective replication feature averaging $0.05 per replicated CD. CD-ROM players can be coupled to television sets or computers so that the user can access textual and visual information as well as audio information stored on a CD-ROM.
It is common practice for most publishers to collect and process their information electronically, that is, on word processors and computers. Their data is maintained in electronic form until it is time to mail it to the subscriber. At that time, the information is printed, subscribers mail labels are attached and the published information is sent via a postal service to the subscriber. Under this system, the costs of printing and delivery are extremely high. Moreover, environmental concerns have necessitated the need to consider paper a critical resource. Accordingly, the need for a new publishing medium has been recognized. For example, see U.S. Pat. Nos. 4,827,508, 4,977,594 and 5,050,213, issued May 2, 1989, Dec. 11, 1990 and Sep. 17, 1991 respectively to Shear.
Subscription services to the home and office through standard postal channels provide subscribers with magazines, trade journals, financial updates and book of the month clubs. These subscription services require the user (subscriber) to pay a fixed amount either in advance or monthly. During the time which the subscription is valid, the publisher continues to mail its information to that subscriber. Moreover, any single user may be the subscriber of a multitude of journals or magazines. It is also likely a single subscriber may hold subscriptions to several magazines published by the same publisher.
Also other types of published or archived information, such as corporate, government, or legal records, are printed on paper for dissemination. When disseminated, such records may inadvertently or intentionally be read by those unauthorized to do so since there is no way to insure that the reader is authorized to access to printed matter. Moreover, since some published corporate or legal information is subject to constant updates which renders the previously published material obsolete, it is preferable but often difficult to purge dated material from circulation.
Again referring to the Shear patents, these systems audit or meter a user's access activity. Because a key to unlock encrypted data is present on the user's hardware, such as a PCMCIA card, the decryption function is inhibited at the user's site in order to prevent unauthorized access to the data. Thus, according to the systems of Shear, access to the information on the portable storage medium, such as a CD-ROM, is available to a user without prior authorization for access. Therefore, there is no way to insure that the reader is authorized to access to the information stored on the CD-ROM prior to the user's access. Furthermore, those systems do not provide a way in which access to out-of-date information can be blocked.
The need for protection of information stored on, for example, CD-ROMs, from unauthorized access needs to be satisfied before such a publication distribution system is acceptable to publishers. Security provided at both the publisher's site and subscriber's site is needed to prevent the unauthorized access to data contained on the media. Moreover, valid subscribers need to be protected when their subscription service is terminated.